In these days, as a steering system installed on a vehicle, there is studied a steering system of steer-by-wire type, i.e., a system configured to turn a wheel of the vehicle in response to operation performed on an operating member by a driver of the vehicle, by electrically controlling a drive source provided in a wheel turning device, in response to the operation, without depending on an operating force applied by the vehicle driver. In this system, an operation input device is not required to transmit an operating force applied to the operating member, to the wheel turning device. In other words, since there is no constructional limitation such as mechanical connection between the operating member and the wheel turning device, the system is capable of employing a wide variety of arrangements. As an example of the system, each of Patent Documents 1 and 2 identified below discloses a system of so-called independent operation type, i.e., a system having a pair of operating members that are operable independently of each other.
[Patent Document 1] JP-2004-244022A
[Patent Document 2] JP-H09-301193A